American Meter Co. (American Meter) (defendant) entered an agreement with Amco Ukrservice (Amco) (plaintiff) to supply utility meters in Ukraine. The agreement was executed in Ukraine, but performance of the contract by American Meter was to take place primarily in Pennsylvania. When the agreement was entered, Ukraine had a still-valid law dating back to the Soviet era that required agreements between Ukrainian companies, such as Amco, and foreign entities, such as American Meter, to be signed by two representatives of the Ukrainian corporation. The agreement was not properly signed as required by the Ukrainian law. The two-signature law was later repealed. American Meter moved for summary judgment on the ground that the agreement was invalid under Ukrainian law. The United States District Court for the Eastern District of Pennsylvania was required to determine whether Pennsylvania law or Ukrainian law applied to the agreement.